1. Field of the Invention
The present invention relates to a storage control system comprising a storage controller, which is connected to a host computer, and which carries out the communication of storage data with this host computer.
2. Description of the Related Art
In a database system that handles large amounts of data, such as a data center, for example, data is managed by using a storage control system constituted independently of a host computer. This storage control system, for example, is constituted comprising a disk array device. The disk array device is constituted by arranging a plurality of storage devices into an array, and is built, for example, on the basis of RAID (Redundant Array of Independent Inexpensive Disks). A logical volume, which is at the least one or more logical storage areas, is formed on a physical storage area provided by the group of storage devices, and this logical volume is provided to the host computer serving as a host (more specifically, to a database program running on the host computer). The host computer can write and read data to and from the logical volume by sending predetermined commands.
As the information society advances, the data managed by databases will increase daily. For this reason, higher performance, larger capacity storage controllers are required, and new storage controllers are being developed to meet the needs of this market. There are two methods for incorporating a new storage controller into a storage control system. The first is a method whereby an old storage controller is completely replaced by a new storage controller, and a storage system is constituted from all new storage controllers (Japanese Patent KOHYO Publication No. H10-508967). The other method is one whereby a new storage controller is added to a storage system comprising old storage controllers, and the old and new storage controllers are used together.
Further, technology for managing the storage area of a physical device in sector units, and for dynamically configuring a logical device in sector units is also well known (Japanese Patent KOKAI Publication No. 2001-337850). In addition, when building a logical device from a plurality of storage devices having different capacities, technology for forming an area in accordance with the storage device having the least capacity, and for forming an area in accordance with the smallest capacity of the remaining capacities is also known (Japanese Patent KOKAI Publication No. H9-288547).